1. Field of the Invention
The present invention relates to an internal combustion engine, and to a vehicle incorporating the same. More particularly, the present invention relates to an internal combustion engine having a reed valve for controlling supply of secondary air to an exhaust system, disposed on a head cover which cooperates with a cylinder head to form a valve motion chamber for accommodating a valve motion apparatus including a camshaft and a main enlarged member extended towards the camshaft for forming form a reed valve chamber integrally provided with the head cover at a location at which the reed valve is disposed, the reed valve chamber being configured to accommodate the reed valve therein, and to a vehicle incorporating the same.
2. Description of the Background Art
There is a known internal combustion engine similar to as described above, for example, as shown in the Japanese Patent Publication No. Sho 62-53688.
It is sometimes required to increase the amount of secondary air introduced into an exhaust system depending on the cylinder capacity of an internal combustion engine. In such circumstances, it is necessary to increase the volume of a reed valve chamber. If it is tried to increase the swelling amount of an enlarged member (by extending the enlarged member) provided on a head cover to the camshaft side in order to satisfy such demand of increasing volume of the reed valve chamber, it is necessary to avoid interference of the enlarged member with a cam of the camshaft. It may also be necessary to avoid interference of the enlarged member with a cam cap which rotatably supports the camshaft with respect to the cylinder head.
Therefore, the swelling amount to the camshaft side is restricted, and where the volume is insufficient, it is necessary to form the enlarged member so as to be extended to the outside of the head cover to increase volume of the reed valve chamber.
However, if the enlarged member is extended (extended) to the outside of the head cover to assure a necessary volume for the reed valve chamber, increase in size of the head cover is required, and interference with some parts around the head cover becomes a problem.
The present invention has been made in view of the situation described above. Accordingly, it is one of the objects of the present invention to provide an internal combustion engine in which the volume of a reed valve chamber is increased while avoiding increase in size of a head cover of the engine.